Using computer simulations, we study the dynamics and interactions of interstitial particles in hard-sphere interstitial solid solutions. We calculate the free-energy barriers associated with their diffusion for a range of size ratios and densities. By applying classical transition state theory to these free-energy barriers, we predict the diffusion coefficients, which we find to be in good agreement with diffusion coefficients as measured using event-driven molecular dynamics simulations. These results highlight that transition state theory can capture the interstitial dynamics in the hard-sphere model system. Additionally, we quantify the interactions between the interstitials. We find that, apart from excluded volume interactions, the interstitial-interstitial interactions are almost ideal in our system. Lastly, we show that the interstitial diffusivity can be inferred from the large-particle fluctuations alone, thus providing an empirical relationship between the large-particle fluctuations and the interstitial diffusivity.
Diffusion and interactions of interstitials in hard-sphere interstitial solid solutions
Berend van der Meer, Emma Lathouwers, Frank Smallenburg, Laura Filion; Diffusion and interactions of interstitials in hard-sphere interstitial solid solutions. J. Chem. Phys. 21 December 2017; 147 (23): 234903. https://doi.org/10.1063/1.5003905
Download citation file: